Phase diagrams for the MOVPE growth of ZnTe and ZnSeTe

The phase diagrams for the MOVPE growth of ZnTe and ZnSeTe have been proposed for the first time, based on the thermodynamic equilibrium established at the solid-vapor interface, The regions for the single condensed phase of ZnTe(s) and of ZnSeTe(s) have been investigated, respectively, Additionally, the growth conditions of appearance for the double condensed phase of ZnTe(s) + Zn(s or l) and ZnTe(s)+ Te(s or l) for the ZnTe system, of ZnSeTe(s) + Zn(s or l) and ZnSeTe(s)+ Te(s or l) for the ZnSeTe system are discussed.

Nuclear shape-phase diagrams

Ground-state energy functions of even-even and odd-A nuclei are derived from simple parameter-dependent Interacting Boson Model (IBM) and Interacting Boson-Fermion Model (IBFM) Hamiltonians. Exact nuclear shape-phase diagrams in the two-parameter (eta, chi) plane are explicitly described using the energy functions on the basis of the condition of phase equilibrium.

Molecular dynamics study on the phase diagrams of linear and branched chain molecules

The particle transfer molecular dynamics is used to study the phase equilibria of linear and branched chain molecules. The scaling of the critical temperature versus chain length is obtained and the critical densities are found to decrease with increasing chain length, which are in agreement with the results of experiment and theory. The phase diagrams of the linear and the branched chain molecules nearly overlap with each other. Moreover, the radial distribution functions of linear and branched chain molecules in gas phase are very similar, but in the liquid phase, they are different for different kinds of chains.

FACTOR-ANALYSIS APPLIED TO X-RAY-DIFFRACTION DIAGRAMS OF POLYMER BLENDS

The feasibility of applying the method of factor analysis to X-ray diffraction diagrams of binary blends of polypropylene and ethylene-propylene-diene terpolymer (PP/EPDM) was examined. The result of mathematical treatment was satisfactory. The number of scattering species and their concentrations in six kinds of PP/EPDM blends were determined. The separation of the spectral peaks of each species in the blends, contributing spectral intensities, was carried out.

STUDY ON FUSIBILITY DIAGRAMS CONTAINING LICL AND PHASE-DIAGRAM OF LICL-KCL-LIF TERNARY BY DIRECT CHLORINATION

In order to avoid the hygroscopicity of LiCl specimem, the method of directly chlorinating Li_2CO_3 with NH_4Cl was successfully introducing into the thermal analysis of the system containing LiCl. The three fusibility diagram of LiCl-KCl, LiClNaCl, LiCl-LiF were determined using the method. The results are in agreement wish the values reported in the literature, and phase diagram of LiCl-KCl-LiF ternary system was constructed based on these results. Temperature of the ternary eutectic, composed of 57.3mol％...

The interaction between poly(vinylpyrrolidone) and reversed micelles of water/AOT/n-heptane

The interactions between poly(vinylpyrrolidone) (PVP) and the reversed micelles composed of water, AOT, and n-heptane are investigated with the aid of phase diagram, measurements of conductivity and viscosity, Fourier transform infrared (FTIR) spectrum, and dynamic light scattering (DLS). The phase diagrams of water/AOT/heptane in the presence of and absence of PVP are given. The conductivity of the water/AOT/heptane reversed micelle without PVP initially increases and then decreases with the increase of water content, ω0 (the molar ratio of water to AOT), while the plots of conductivity (K) versus ω0 of the reversed micelle in the presence of PVP depend on the PVP concentrations. The plot of K versus ω0 with 2.0%wt PVP is similar to that without PVP. Only the ω0,max (the water content that the maximum conductivity corresponds to) is larger than that without PVP. Nevertheless, the conductivity of the reversed micelle containing more than 4%wt PVP always rises with the increase of the water content in the measured range. The DLS results indicate that the hydrodynamic radius (Rh) in the presence and absence of PVP rises with the increase of ω0. The plots with PVP and without PVP have almost the same value when ω0<17; and after that, it quickly increases with the increase of ω0. It is interesting to find that there is almost no effect of the PVP concentration on the viscosity and Rh of the reversed micelle at ω0 = 15. The FTIR results suggest that the contents of SO3--bound water and Na+-bound water both decrease with PVP added, while the content of the bulky-like water increases. However, the trapped water in the hydrophobic chain of the surfactant is nearly unaffected by PVP. It is also found from the FTIR that the carbonyl group stretching vibration of AOT is fitted into two sub-peaks, which center at 1740 and 1729 cm-1, corresponding to the trans and cis conformations of AOT, respectively.

Distribution, stability, bifurcations and catastrophe of steady rotation of a symmetrical heavy gyroscope with viscous-liquid-filled cavity

The number, the angles of orientation and the stability in Rumyantsev Movchan's sense of oblique steady rotations of a symmetric heavy gyroscope with a cavity completely filled with a uniform viscous liquid, possessing a fixed point 0 on its symmetric axis. are given for various values of the parameters. By taking the square of the upright component of the angular momentum M2 as a control parameter, three types of bifurcation diagrams of the steady rotations, two types of jumps and two kinds of local catastrophes, one being the symmetric reduced cusp type and the other being of the symmetric reduced butterfly type, are obtained. By taking account of the M2-damping owing to the moment of unavoidable faint friction, two different modes for the gyroscope, initially in a stable quasi-steady upright rotation with a nutation angle theta(s) equal to zero, to topple over are found.

Bulk crystal growth and efficient diode-pumped laser performance of Yb 3+:Sc2SiO5

A bulk crystal of Yb:Sc2SiO5 (Yb:SSO) with favorable thermal properties was successfully obtained by the Czochralski method. The energy level diagrams for Yb:SSO crystal were determined by optical spectroscopic analysis and semi-empirical crystal-field calculations using the simple overlap model. The full width at half maximum of the absorption band centering at 976 nm was calculated to be 24 nm with a peak absorption cross-section of 9.2x10(-21) cm(2). The largest ground-state splitting of Yb3+ ions is up to 1027 cm(-1) in a SSO crystal host. Efficient diode-pumped laser performance of Yb:SSO was primarily demonstrated with a slope efficiency of 45% and output power of 3.55 W.

东灵山地区辽东栎群中植物种群的时空格局研究

在北京东灵山地区以辽东栎（Quercus liaotungensis Koidz.）林群落为主要对象，研究了辽东栎种群和主要伴生种的空间格局、种间联结以及辽东栎种子雨的时间格局，井对空间格局的表达方法进行尝试性的探讨。 对辽东栎林群落中主要乔木树种辽东栎、大叶白蜡（Fraxinus thynchophylla）和五角枫（Acer mono）种群空间格局与动态的考察结果显示：各种群大多表现出聚集分布的趋势;辽东栎种群在各个龄级层均显示出较强优势，但种群内竞争激烈，龄级结构相对稳定;人叶白蜡的幼苗对环境适应能力较强，在成熟林中呈现出较五角枫种群更明显的增长型趋势：幼林中3个种群均呈衰退型趋势。 种间联结性的测定结果较好地反映了植物对环境的适应性，用关联分析法作出的树状图利用临界种将样方划分为若干组，体现出小生境之间的差异，反映了植物对其生境亦具有一定指示作用。 辽东栎种子雨的时间格局研究结果表明：种群种子雨密度随时间的变化呈正态分布趋势，种群水平利个体水平的种子雨累积随时间变化均符台Logistic曲线，具有很高的相关性。 空间格局表达方法的探讨显示：可以用集合论的方法对数学模型进行形象表达。

DTADH and quantum critical phenomena caused by anisotropy and external magnetic field for spin-1/2 Heisenberg diamond chains

Using the transfer matrix renormalization group (TMRG) method, we study the connection between the first derivative of the thermal average of driving-term Hamiltonian (DTADH) and the trace of quantum critical behaviors at finite temperatures. Connecting with the exact diagonalization method, we give the phase diagrams and analyze the properties of each phase for both the ferromagnetic and anti-ferromagnetic frustrated J(3) anisotropy diamond chain models. The finite-temperature scaling behaviors near the critical regions are also investigated. Further, we show the critical behaviors driven by external magnetic field, analyze the formation of the 1/3 magnetic plateau and the influence of different interactions on those critical points for both the ferrimagnetic and anti-ferromagnetic distorted diamond chains.

In-Situ Boron and Aluminum Doping and Their Memory Effects in 4H-SiC Homoepitaxial Layers Grown by Hot-Wall LPCVD

The in-situ p-type doping of 4H-SiC grown on off-oriented (0001) 4H-SiC substrates was performed with trimethylaluminum (TMA) and/or diborane (B2H6) as the dopants. The incorporations of Al and B atoms and their memory effects and the electrical properties of p-type 4H-SiC epilayers were characterized by secondary ion mass spectroscopy (SIMS) and Hall effect measurements, respectively. Both Al- and B-doped 4H-SiC epilayers were p-type conduction. It was shown that the profiles of the incorporated boron and aluminum concentration were in agreement with the designed TMA and B2H6 flow rate diagrams. The maximum hole concentration for the Al doped 4H-SiC was 3.52x10(20) cm(-3) with Hall mobility of about 1 cm(2)/Vs and resistivity of 1.6 similar to 2.2x10(-2) Omega cm. The heavily boron-doped 4H-SiC samples were also obtained with B2H6 gas flow rate of 5 sccm, yielding values of 0.328 Omega cm for resistivity, 5.3x10(18) cm(-3) for hole carrier concentration, and 7 cm(2)/VS for hole mobility. The doping efficiency of Al in SiC is larger than that of B. The memory effects of Al and B were investigated in undoped 4H-SiC by using SIMS measurement after a few run of doped 4H-SiC growth. It was clearly shown that the memory effect of Al is stronger than that of B. It is suggested that p-type 4H-SiC growth should be carried out in a separate reactor, especially for Al doping, in order to avoid the join contamination on the subsequent n-type growth. 4H-SiC PiN diodes were fabricated by using heavily B doped epilayers. Preliminary results of PiN diodes with blocking voltage of 300 V and forward voltage drop of 3.0 V were obtained.

基于Venn图的层次信息可视化

为解决具有层次结构的大量信息的可视化问题,文中给出了用嵌套圆表达树型结构信息的可视化方法,即用相切的圆表示兄弟节点,嵌套的圆表示父子节点,圆的位置、大小和颜色分别表示树节点的不同属性信息.同层的兄弟节点并排排列,圆的排列算法快速、稳定、紧密且不相互重叠,排列圆的个数与时间呈线性关系,该排列算法适于大量信息的可视化,既能快速显示大数据集的整体视图,又方便查看细节信息;既能清楚地表达复杂信息间的层次关系,又能显示树节点的属性.该方法可用于文件系统的可视化,实例表明该方法简单、实用、高效、可靠.

端羟基丁腈共聚物对环氧树脂的增韧

国外早期曾用丁腈橡胶增韧环氧树脂。六十年代后，主要用端羧基丁腈共聚物（丁腈羧，CTBN）作为增韧剂增韧环氧树脂。但丁腈羧的合成方法中，引发剂引发效率很低，产品纯制比较麻烦，要使用较多溶剂，因此，成本较高。这是使用丁腈羧作为增韧剂的缺点。针对这种情况，朴光哲曾研究用丁腈羟增韧环氧树脂，方法是先将羟基转化成羧基后，，再用于增韧环氧树脂。使用丁腈羟作为增韧剂的原因是因为丁腈羟合成较易，是遥瓜型液体橡胶中价格较低的品种。我们认为，用丁腈羟增韧环氧树脂是适宜的，可以解决用丁腈羧作为增韧剂所存在的问题。但上述方法是经过端基转化，间接使用丁腈羟的方法。此论文的内容是研究直接使用丁腈羟作为增韧剂的方法。即略去端基转化过程，这样可以达到简化工艺的目地。另外，在固化体系中，增加酸酐用量。使酸酐既与丁腈羟反应，也与环氧基反应，又与仲羟基反应。这样有利于改进增韧环氧树脂的结构和性能。按照这种设想，设计了增韧环氧树脂固化体系。在此基础上，所进行的研究工作内容包括：1，固化反应动力学；2，固化物的力学性质；3，固化物的形态结构；4，固化物的TTT图；5，固化物的热分解。用示差扫描量热计及红外光谱对六氢邻苯二甲酸酐固化的增韧环氧树脂进行了固化反应动力学的研究，得到固化温度，固化时间和转化率的关系式为：1/0.2 [1/((1-P)~(0.2)) - 1] = kt其中，P为转率；K为表观反应速率常数；t为反应时间。通过此式，即可达到控制固化反应的目地。同时还得到该体系的固化速率主要决定于酸酐的扩散过程，其原因认为是由于固化反应过程中，微观凝聚相的形成。对不同固化体系增韧环氧树脂的力学性能研究表明。固化物性能的变化一般可分为增韧，增柔，相倒转三个阶段。丁腈羟增韧环氧树脂的增韧效果与所选固化剂种类，丁腈羟用量、丁腈羟中丙烯腈的含量有关。在所研究的酸酐固化体系中，以六氢邻苯二甲酸酐固化体系的增韧效果最好。从固化物的综合性能看，增韧剂用量以10～20份，丁腈羟中丙烯腈含量以15%左右为宜。丁腈羟用量为10份的增韧体系中，抗剪强度提高20%达27MPa，抗张强度提高41%，达80MPa。断裂伸长提高一倍，断裂功提高三倍，断裂表面能提高十倍。而杨氏模量仅降低7%倍。固化物各阶段的力学性能取决于固化物的形态结构。其形态结构与环氧树脂固化体系中各组分的相容性及固化速度密切相关。未增韧的环氧树脂是均相，增韧环氧树脂是两相结构。由橡胶微区和环氧基体组成，橡胶微区的大小和组成与丁腈羟用量，橡胶中丙烯腈含量，固化温度有关。随丁腈羟用量加大，橡胶微区增多，直径分布增大。用量增到一定程度，发生相倒转现象。固化剂不同，微区和基体的结构差异很大。六氢邻苯二甲酸酐，70酸酐，甲基四氢邻苯二甲酸酐固化体系的形态结构相似。甲基内次甲基四氢邻苯二甲酸酐固化体系的橡胶微区是由橡胶-环氧组成的橡胶富集相。桐油酸酐固化体系则有更小的橡胶微区出现。用扫辨仪研究了增韧和未增韧环氧树脂的等温固化过程。作出TTT图。得出两体系的固化行为相似，增韧环氧树脂的玻璃化曲线略有推迟，Tg_0 = -23 ℃, Tg_∞ = 85 ℃，(未增韧环氧树脂Tg_∞ = 88 ℃)。通过热重分析法研究以六氢邻苯二甲酸酐为固化剂的丁腈羟增韧环氧树脂在空气中分解的情况。起始分辨温度为250 ℃。表现活化能由180kJ/mol提高到280kJ/mol。分解过程中有一缓慢失重阶段，在酸酐用量较大的情况下，起始分解温度降低，说明增大酸酐用量并未提高固化物交联密度。总之，用丁腈羟直接增韧环氧树脂是一个适宜的增韧方法。解决了用丁腈羧作为增韧剂的缺点。为环氧树脂的增韧技术，增添了新的内容。